The present invention relates to a throttle valve opening degree controlling apparatus for an internal combustion engine and, more particularly to a throttle valve opening degree controlling apparatus for an internal combustion engine in which for an internal combustion engine suitable for a gasoline engine of an automobile etc. the fuel supply amount into the internal combustion engine is controlled electronically via an actuator for controlling an opening degree of a throttle valve.
In a conventional internal combustion engine such as a gasoline engine, a fuel is adhered to an inner wall surface portion of an intake passage such as an intake pipe of the internal combustion engine. As a result, it has been known that it is necessary to carry out a correction or an amendment processing for an air-fuel ratio (A/F) control.
In the conventional internal combustion engine apparatus, for example in U.S. Pat. No. 4,357,923, the difference of the air-fuel ratio (A/F) due to the above stated fuel being adhered to the inner wall surface portion of the intake passage (herein-after called as an intake surface adhesion fuel) has been compensated in accordance with an adjustment of a correction fuel injection amount against a predetermined supply fuel amount.
In the above stated conventional adjustment technique for the correction fuel injection amount, when the intake air amount changes suddenly such as the quick accelerating operation or the quick decelerating operation on the engine, it impossible completely to carry out a follow-up characteristic for the fuel injection amount control.
So as to compensate such an insufficiency in the follow-up characteristic for the fuel injection amount control, the time lag in the follow-up for the fuel injection amount control is estimated at the sudden change state in the intake air amount, and the above stated correction fuel injection amount is calculated according to a result of the estimation for the follow-up characteristic for the fuel injection amount.